One primary purpose of ocean colonization is the expansion of livable area. Other possible benefits include expanded access to undersea resources, novel forms of governance (for instance micronations), and new recreational activities.

Lessons learned from ocean colonization may prove applicable to space colonization. The ocean may prove simpler to colonize than space and thus occur first, providing a proving ground for the latter. In particular, the issue of sovereignty may bear many similarities between ocean and space colonization; adjustments to social life under harsher circumstances would apply similarly to the ocean and to space; and many technologies may have uses in both environments.